History books (and shows on the Investigation Discovery Network) are filled with stories about crime duos. Most of these stories focus on criminal couples like Bonnie and Clyde, but sibling pairs come up as well, the most recent alleged example being the Tsarnaev brothers, the two suspects in the Boston Marathon bombings. As the police continue to search for Dzhokar, the younger of the two, here are five sets of siblings who have teamed together to commit crimes.

The Carr BrothersIn Wichita, Kan., in December 2000, brothers Reginald and Jonathan Carr went on a six-day crime and killing spree that terrorized the community, and later led to criticisms of the media's alleged double standards when covering race-related murders.

The spree started on December 8 when the brothers robbed a 23-year-old assistant baseball coach, and continued three days later when they fatally wounded a 55-year-old cellist during a car jack. Then on December 14, the brothers broke into a random home, where five men and women in their twenties were spending the night. After ransacking the house for valuables, they subjected the group to sexual abuse, then drove them to a construction site and shot each of them in the head. One of the five escaped — her metal barrette deflected the bullet — and later identified the brothers.

The court did not treat the killings as hate crimes, ruling that there was no evidence of racial motivation. But several prominent bloggers insisted that the mainstream media avoided covering the crime for reasons of political correctness — the perpetrators were black, the victims were white. Conservative blogger Thomas Sowell, for example, accused the media of playing up "vicious crimes by whites against blacks" while playing down "vicious crimes by blacks against whites."

Other writers pointed to a different double standard. The Wichita Eagle noted that eight days before the "Wichita Massacre," as it became known, four young black people were killed as well, but that received almost no media attention at all.

The Menendez BrothersChildren of the 90s remember the Menendez brothers: Two young men from Beverly Hills, Calif., who killed their affluent parents on August 20, 1989, then went on a six-month spending binge with their money.

The media obsessed over the case's strange details: How immediately after the murder the brothers saw License to Kill, the James Bond movie, and used it as an alibi; how a week before the murder the mother confided to her therapist that she worried her sons were sociopaths; and how one brother bought a chicken-wing restaurant with his parents' money following their deaths. The media also glommed onto the brothers' background: Their father was an executive in the entertainment industry, both went to private schools, and the older brother Lyle was briefly enrolled in Princeton.

After two deadlocked juries, Los Angeles prosecutors retried the brothers in a courtroom that did not allow cameras. The new jury found the Menendezes guilty of two counts of first degree murder. The judge sentenced them to life in prison.

The Scissor SistersLinda and Charlotte Mulhall, 30 and 23, respectively, were the subjects of one of the most hotly covered murder cases in Ireland's history. On what sounds like one "crazy night," the women killed and dismembered their mother's boyfriend, Farah Swaleh Noor, who allegedly physically abused their mother.

The events leading up to the murder propelled it to the front page. Newspapers divulged details of the sisters' troubled histories, which included prostitution, crime, and drug abuse. On the night of the murder, the sisters allegedly took ecstasy pills with their mother and the victim.

The details of what followed are greusome — read more here if you have a strong stomach. To give you a taste: The police were notified when part of the victim's leg with a sock still on it was spotted floating down a river near Croke Park ten days later.

A court found Charlotte guilty of murder and Linda guilty of manslaughter, and gave the girls life and 15 years, respectively. Their father, John Mulhall, hanged himself in Dublin's Phoenix Park when he heard the verdict.

The Spahalski TwinsSubjects of a 2010 book called Killer Twins, the Spahalski twins grew up committing crimes together. In their youth, they would challenge each other to steal bigger and bigger items, until on one such excursion, Stephen Spahalski killed a store owner in 1971.

While his brother serving time in jail, Robert's life fell apart. He became addicted to crack cocaine, and eventually began committing murders himself. Now considered a serial killer, Robert killed four people, including his girlfriend, who was strangled with an electrical cord.

The brothers were estranged for most of their lives, and when a police officer showed Stephen an article about his brother confessing to four murders, he said, "I thought I was the only murderer in the family."

The Kray BrothersNotorious London gangsters in the 50s and 60s, the Kray brothers had the unique reputation of both running "The Firm" — a violent gang in London's East End — and prospering as night club owners who partied with clients like Judy Garland and Frank Sinatra.

Called "Britain's Godfathers," the brothers were known for a variety of gang-related crime — extortion, armed robbery, arson, hijacking, assault, torture, murder — and were said to work seamlessly as a team. John Pearson, author of The Cult of Violence: The Untold Story of the Krays, claims, "In gang fights they seemed to be telepathic, as if they were one."

Police finally arrested them in 1968 for the murders of Jack "The Hat" McVitie and George Cornell, and a judge sent them both to prison. Ronnie died of a heart attack in 1995, and Reggie of cancer in 2000.